Caloric restriction reduces age at menopause: the effect of the 1944-1945 Dutch famine.

OBJECTIVE: To assess the effect of caloric restriction, as endured during the 1944-1945 Dutch famine, on the age at which natural menopause occurs and to identify specific vulnerable age periods in which caloric restriction has the largest effect. DESIGN: This was a population-based cohort study conducted in Utrecht, the Netherlands. Between 1983 and 1986, 9,471 women aged 40 to 73 years at the time of interview were classified regarding their exposure to the famine. Age at natural menopause was obtained from all available data, retrospectively as well as prospectively. We estimated differences in mean age at natural menopause between famine exposure categories (not, moderately, and severely exposed), with adjustment for smoking, parity, socioeconomic status, body mass index, age at menarche, and year of birth. RESULTS: Women experienced natural menopause on average 0.36 years earlier (95% CI: -0.60, -0.11) when severely exposed to the famine and 0.06 years earlier (95% CI: -0.22, 0.09) when moderately exposed compared with the unexposed women. This effect was particularly pronounced in those severely exposed from 2 to 6 years of age: -1.83 years (95% CI: -3.03, -0.63). CONCLUSIONS: Our findings suggest that caloric restriction decreases age at natural menopause. Early childhood seems to be a particularly sensitive age period for this effect.

Utility of zinc protoporphyrin in management of whole blood donors.

BACKGROUND: Deferral for low hemoglobin (Hb) increases the likelihood that donors do not return for future donations. Zinc protoporphyrin (ZPP) has been described as a sensitive marker of iron-deficient erythropoiesis, before Hb decreases. It is a relatively cheap, rapid, and easy-to-perform measurement in a drop of whole blood. To assess the utility of ZPP measurement in donor management we examined whether ZPP and Hb levels among first-time donors differ from repeat donors. We further explored whether ZPP increases over subsequent donations at a donor population level and whether increasing ZPP levels coincide with decreasing Hb levels and donor deferral. STUDY DESIGN AND METHODS: We included first-time (n = 4983) and repeat (n = 3533) whole blood donors from the ZPP and Iron in the Netherlands Cohort (ZINC) study. ZPP and Hb were measured at each subsequent donation during a 4-year period after inclusion in the study. RESULTS: Median ZPP levels were higher in repeat than in first-time donors. In first-time donors, especially women, ZPP levels were increased with a corresponding decline in Hb levels over subsequent donations. ZPP levels were increased among first-time donors deferred for low Hb. CONCLUSION: Our results suggest that adding ZPP to Hb measurements in the daily blood collection setting, especially for first-time donors and first-time female donors may add to the identification of a donor subpopulation with low functional iron stores.

Blood donors' physical characteristics are associated with pre- and post-donation symptoms - Donor InSight.

BACKGROUND: Observational data suggest that some donors might benefit from donating while others may be harmed. The aim of this study was to investigate the prevalence and potential, routinely measured, determinants of pre- and post-donation symptoms. MATERIALS AND METHODS: In Donor InSight, questionnaire data from 23,064 whole blood donors (53% female) were linked to routinely measured data on donors' physical characteristics (haemoglobin, blood pressure, body mass index and estimated blood volume) from the Dutch donor database. Absolute and relative associations between donors' physical donor and the presence of pre- and post-donation symptoms were studied using multivariable logistic regression. RESULTS: Pre-donation symptoms (lack of energy, headaches) were reported by 3% of men and 3% of women. Five percent of men and 4% of women reported positive post-donation symptoms (feeling fit, fewer headaches). Negative symptoms (fatigue, dizziness) were more common, occurring in 8% of men and 19% of women. All the studied donors' physical characteristics were positively associated with pre- and positive post-donation symptoms and negatively associated with negative symptoms. Body mass index was most consistently and independently associated with symptoms. DISCUSSION: Donors' physical characteristics, in particular body mass index, were consistently associated with pre- and post-donation symptoms. This indicates that subgroups of donors more and less tolerant to donation might be identifiable using routinely measured data. Further research is warranted to study underlying mechanisms and potential strategies to predict and prevent donor reactions.

High prevalence of subclinical iron deficiency in whole blood donors not deferred for low hemoglobin.

BACKGROUND: Blood donors that meet the hemoglobin (Hb) criteria for donation may have undetected subclinical iron deficiency. The aim of this study was to assess the prevalence of subclinical iron deficiency in whole blood donors with Hb levels above cutoff levels for donation by measuring zinc protoporphyrin (ZPP) levels. In addition, prevalence rates based on other iron variables were assessed for comparison. STUDY DESIGN AND METHODS: The study population comprised 5280 Dutch whole blood donors, who passed the Hb criteria for donation. During donor screening, Hb levels were measured in capillary samples (finger prick), and venous blood samples were taken for measurements of ZPP and other iron variables. These variables included ferritin, transferrin saturation, soluble transferrin receptor (sTfR), hepcidin, red blood cell mean corpuscular volume (MCV), and mean cell Hb (MCH). RESULTS: With a ZPP cutoff level of at least 100 µmol/mol heme, subclinical iron deficiency was present in 6.9% of male donors and in 9.8% of female donors. Based on other iron variables, iron deficiency was also observed. Prevalence rates ranged from 4.8% (based on transferrin saturation) to 27.4% (based on hepcidin concentration) in men and from 5.6% (based on sTfR concentration) to 24.7% (based on hepcidin concentration) in women. CONCLUSION: Results from this study showed that subclinical iron deficiency is prevalent among blood donors that meet the Hb criteria for blood donation, based on ZPP levels and on other iron variables. This finding needs attention because these donors are at increased risk of developing iron deficiency affecting Hb formation and other cellular processes.

Erythrocytapheresis versus phlebotomy in the initial treatment of HFE hemochromatosis patients: results from a randomized trial.

BACKGROUND: Standard treatment of newly diagnosed HFE hemochromatosis patients is phlebotomy. Erythrocytapheresis provides a new therapeutic modality that can remove up to three times more red blood cells per single procedure and could thus have a clinical and economic benefit. STUDY DESIGN AND METHODS: To compare the number of treatment procedures between erythrocytapheresis and phlebotomy needed to reach the serum ferritin (SF) target level of 50 µg/L, a two-treatment-arms, randomized trial was conducted in which 38 newly diagnosed patients homozygous for C282Y were randomly assigned in a 1:1 ratio to undergo either erythrocytapheresis or phlebotomy. A 50% decrease in the number of treatment procedures for erythrocytapheresis compared to phlebotomy was chosen as the relevant difference to detect. RESULTS: Univariate analysis showed a significantly lower mean number of treatment procedures in the erythrocytapheresis group (9 vs. 27; ratio, 0.33; 95% confidence interval [CI], 0.25-0.45; Mann-Whitney p < 0.001). After adjustments for the two important influential factors initial SF level and body weight, the reduction ratio was still significant (0.43; 95% CI, 0.35-0.52; p < 0.001). Cost analysis showed no significant difference in treatment costs between both procedures. The costs resulting from productivity loss were significantly lower for the erythrocytapheresis group. CONCLUSION: Erythrocytapheresis is highly effective treatment to reduce iron overload and from a societal perspective might potentially also be a cost-saving therapy.

Lifetime cumulative number of menstrual cycles and serum sex hormone levels in postmenopausal women.

OBJECTIVE: Lifetime cumulative number of menstrual cycles is related to breast cancer risk. The aim of this study is to investigate the relation between this index and serum sex hormone levels in postmenopausal women. METHODS: Cross-sectional study including 860 naturally postmenopausal Dutch participants of the European Prospective Investigation into Cancer and Nutrition. Lifetime cumulative number of menstrual cycles was computed using questionnaire data on ages at menarche and menopause, number of pregnancies, breastfeeding, oral contraceptive use (OC) and regularity pattern. Measurements of hormones included estrone (E1), estradiol (E2), andostrenedione, testosterone, sex-hormone binding globulin (SHBG) and dehydroepiandrostenedione sulfate (DHEAS). The relation between the lifetime cumulative number of menstrual cycles and hormone levels was assessed using analysis of covariance. Relations between reproductive characteristics and hormone levels were also studied. Adjustments for characteristics at blood collection included age, years since menopause, BMI, hormone replacement therapy use, OC use, smoking habits, alcohol intake and physical activity were done. RESULTS: Lifetime cumulative number of cycles was related with SHBG; participants in the lowest category had higher SHBG levels. For the separate characteristics, DHEAS and androstenedione increased significantly with increasing age at menarche, while androstenedione and testosterone decreased with increasing age at menopause. For the parity characteristics, SHBG levels increased according to the number of live births. CONCLUSIONS: Lifetime cumulative number menstrual cycles was related only to SHBG. Therefore, free levels of estrogens or androgens may be related to this number of menstrual cycles estimate, reflecting lifetime exposure to ovarian hormones.

No relationship between circulating levels of sex steroids and mammographic breast density: the Prospect-EPIC cohort.

BACKGROUND: High breast density is associated with increased breast cancer risk. Epidemiologic studies have shown an increase in breast cancer risk in postmenopausal women with high levels of sex steroids. Hence, sex steroids may increase postmenopausal breast cancer risk via an increase of breast density. The objective of the present study was to study the relation between circulating oestrogens and androgens as well as sex hormone binding globulin (SHBG) in relation to breast density. METHODS: We conducted a cross-sectional study among 775 postmenopausal women, using baseline data of a random sample of the Prospect-EPIC study. Prospect-EPIC is one of two Dutch cohorts participating in the European Prospective Investigation into Cancer and Nutrition, and women were recruited via a breast cancer screening programme. At enrolment a nonfasting blood sample was taken and a mammogram was made. Oestrone, oestradiol, dehydroepiandrosterone sulfate, androstenedione, testosterone and SHBG levels were measured, using double-antibody radioimmunoassays. Concentrations of free oestradiol and free testosterone were calculated from the measured oestradiol, testosterone and SHBG levels Mammographic dense and nondense areas were measured using a semiquantitative computerized method and the percentage breast density was calculated. Mean breast measures for quintiles of hormone or SHBG levels were estimated using linear regression analyses. RESULTS: Both oestrogens and testosterone were inversely related with percent breast density, but these relationships disappeared after adjustment for BMI. None of the sex steroids or SHBG was associated with the absolute measure of breast density, the dense area. CONCLUSION: The results of our study do not support the hypothesis that sex steroids increase postmenopausal breast cancer risk via an increase in breast density.

Menstruation during and after caloric restriction: the 1944-1945 Dutch famine.

OBJECTIVE: To investigate the relation between exposure to the 1944-45 Dutch famine and concurrent and subsequent menstrual disturbances. DESIGN: Cohort study. SETTING: Doorlopend Onderzoek Mammacarcinoom breast cancer screening project, Utrecht, the Netherlands. PATIENT(S): Between 1983 and 1986, approximately 12,500 women (born 1911-41) reported their individual famine experiences. MAIN OUTCOME MEASURE(S): Irregular menstruation during the famine; time to regular menses after menarche, and menstrual patterns in adulthood after childhood famine. RESULT(S): The famine had a direct impact on menstruation. The odds ratio (OR) of concurrent irregular menses in severely versus unexposed women was 8.85 (95% confidence interval [CI], 7.31-10.70). Women exposed to severe famine before menarche were 1.51 (95% CI, 1.15-1.98) times more likely to experience irregular menses for a prolonged time after menarche compared with the unexposed. This association was stronger in women with an early menarche. When the menstrual pattern was assessed in adulthood by menstrual diaries, a nonsignificant tendency of increased irregularity (OR, 1.13; 95% CI, 0.82-1.54) and regular but long menstrual cycles (OR, 1.41; 95% CI, 0.89-2.23) was observed in women exposed to severe famine. CONCLUSION(S): Famine relates to concurrent menstrual irregularity, and exposure in childhood seems to affect the subsequent menstrual pattern.

Therapeutic erythrocytapheresis versus phlebotomy in the initial treatment of hereditary hemochromatosis - A pilot study.

Hereditary Hemochromatosis (HH) is a genetic disorder of iron metabolism, resulting in excessive iron overload. Currently, phlebotomy is the standard effective treatment that prevents progression of tissue damage. Aim of the therapy is to reach ferritin levels between 20 and 50mugl(-1). In patients with total iron stores of more than 30g, intensive treatment by means of weekly phlebotomies during 2-3 years is required to reach this aim. More recently mechanical removal of erythrocytes through therapeutic erythrocytapheresis (TE) has become a new therapeutic modality. By means of TE, up to 1000ml erythrocytes per session can be removed, depending on patient characteristics, compared to 250ml erythrocytes per phlebotomy. Thus, TE potentially offers a more efficient method of removing iron overload with less procedures in a shorter treatment period. In a pilot study between 2002 and 2005, results from a group of HH patients treated with TE (N=6) were compared to the results of a historical control group of HH patients (N=6) treated with phlebotomy. The results showed a reduction of almost 70% in both the total number and the duration of treatments in the TE group. Although, the procedure costs compared on the basis of a single TE session were higher, the total costs for the whole treatment were comparable or cheaper with the use of TE. Future prospective studies are needed to compare both therapies in a randomized setting.

Premenopausal insulin-like growth factor-I serum levels and changes in breast density over menopause.

BACKGROUND: A high proportion of glandular and stromal tissue in the breast (percentage breast density) is a strong risk factor for breast cancer development. Insulin-like growth factor-I (IGF-I) is hypothesized to influence breast cancer risk by increasing breast density. OBJECTIVES: We studied the relation between premenopausal circulating IGF-I levels and premenopausal and postmenopausal, absolute nondense and dense area, and percentage breast density as well as changes in these measures over menopause. DESIGN AND METHODS: Mammograms and blood samples of 684 premenopausal participants of the Prospect-European Prospective Investigation into Cancer and Nutrition cohort were collected at baseline. A second mammogram of these women was collected after they became postmenopausal. Premenopausal IGF-I levels were measured in serum. Premenopausal and postmenopausal breast measures were assessed using a computer-assisted method. Mean values of breast measures were calculated for quartiles of serum IGF-I using linear regression analysis. RESULTS: Women with higher premenopausal IGF-I levels showed a slightly smaller decrease in dense area over menopause (-12.2 cm2 in the highest versus -12.9 cm2 in the lowest quartile; P trend = 0.58) and, at the same time, a smaller increase in the nondense (fat) area (P trend = 0.09). Due to the changes over menopause, high premenopausal IGF-I serum levels were associated with lower nondense area (P trend = 0.05), somewhat higher dense area (P trend = 0.66), and consequently higher percentage breast density (P trend = 0.02) after menopause. CONCLUSION AND DISCUSSION: Women with higher premenopausal IGF-I levels have a smaller increase in nondense area and also a slightly smaller decrease in absolute dense area during menopause, resulting in higher breast density after menopause.

Postmenopausal hormone therapy and changes in mammographic density.

PURPOSE: Hormone therapy (HT) use has been associated with an increased breast cancer risk. We explored the underlying mechanism further by determining the effects of HT on mammographic density, a measure of dense tissue in the breast and a consistent breast cancer risk factor. PATIENTS AND METHODS: A total of 620 HT users and 620 never users from the Dutch Prospect-European Prospective Investigation into Cancer and Nutrition (EPIC) cohort and 175 HT users and 161 never users from the United Kingdom EPIC-Norfolk cohort were included. For HT users, one mammogram before and one mammogram during HT use was included. For never users, mammograms with similar time intervals were included. Mammographic density was assessed using a computer-assisted method. Changes in density were analyzed using linear regression. RESULTS: The median time between mammograms was 3.0 years and the median duration of HT use was 1 year. The absolute mean decline in percent density was larger in never users (7.3%) than in estrogen therapy users (6.4%; P = .22) and combined HT users (3.5%; P < .01). The effect of HT appeared to be high in a small number of women, whereas most women were unaffected. CONCLUSION: Our results suggest that HT use, and especially estrogen and progestin use, slows the changes from dense patterns to more fatty patterns that are normally seen in women with increasing age. Given that it is postulated that lifetime cumulative exposure to high density may be related to breast cancer risk, a delay in density decline in HT users potentially could explain their increased breast cancer risk.

Innate handedness and disease-specific mortality in women.

BACKGROUND: Left-handedness has been reported to be associated with reduced life expectancy, but the evidence is far from conclusive. METHODS: We studied the association between innate handedness and total mortality, as well as cause-specific mortality, in a cohort of 12,178 middle-aged Dutch women who were followed for almost 13 years. The relation between handedness and mortality was analyzed using Cox regression in a case-cohort approach, in which a random sample of 1500 women was used to represent person-years under observation for the entire cohort. RESULTS: During a median follow-up of 12.6 years, 252 women died. Hazard ratios comparing left-handed women with other women were 1.4 for all-cause mortality (95% confidence interval = 0.9-2.0), 1.7 for total cancer mortality (1.0-2.7), 2.0 for breast cancer mortality (0.8-4.6), 4.6 for colorectal cancer mortality (1.5-14.3), 1.3 mortality from diseases of the circulatory system (0.5-3.3), and 3.7 for cerebrovascular mortality (1.1-12.1), after adjusting for potential confounders (socioeconomic status, age, body mass index, and cigarette smoking status at study recruitment). CONCLUSIONS: Left-handedness is associated with higher mortality in women.

Transient caloric restriction and cancer risk (The Netherlands).

Over the past century, many animal experiments have shown that caloric restriction can reduce the risk of cancer, a finding that proved to be highly reproducible. Many papers have been published on its potential for human health, but until know little evidence is available on its actual effects in humans. In Utrecht, The Netherlands, we have been investigating the effects of the 1944-1945 Dutch famine on breast cancer risk factors and breast cancer risk, and paradoxically the relatively short-term famine seemed to be related to increased breast cancer risk in later life. One of the differences between the famine situation and the large body of evidence from animal experiments is the duration of caloric restriction. Almost all animal experiments investigated sustained caloric restriction and information on the effects of short-term transient caloric restriction is very scarce. A search in the literature identified some animal experiments on short-term transient caloric restriction and these seemed to be at least supportive to the famine findings. Because caloric restriction in humans for preventive health measures would be mostly short-term, it is important to extend animal research on short-term caloric restriction.

Comparing correlations of continuous observations from two independent populations using a sequential approach.

A sequential study design generally makes more efficient use of available information than a fixed sample counterpart of equal power. This feature is gradually being exploited by researchers in genetic and epidemiological investigations that utilize banked biological resources and in studies where time, cost and ethics are prominent considerations. Recent work in this area has focussed on the sequential analysis of matched case-control studies with a dichotomous trait. In this paper, we extend the sequential approach to a comparison of the associations within two independent groups of paired continuous observations. Such a comparison is particularly relevant in familial studies of phenotypic correlation using twins. We develop a sequential twin method based on the intraclass correlation and show that use of sequential methodology can lead to a substantial reduction in the number of observations without compromising the study error rates. Additionally, our approach permits straightforward allowance for other explanatory factors in the analysis. We illustrate our method in a sequential heritability study of dysplasia that allows for the effect of body mass index and compares monozygotes with pairs of singleton sisters.

Physical activity in relation to mammographic density in the dutch prospect-European prospective investigation into cancer and nutrition cohort.

BACKGROUND: Evidence accumulates that physical inactivity is one of the few modifiable risk factors for breast cancer. The mechanism through which physical inactivity affects breast cancer risk is not clear. The study aim was to investigate the association between physical activity and breast density because mammographic density is strongly associated with breast cancer risk. METHODS: We did a cross-sectional study in 620 women, of ages 49 to 68 years and participants of the Dutch Prospect-European Prospective Investigation into Cancer and Nutrition cohort. A self-administered questionnaire was used to obtain information on duration and intensity of physical activity (recreational, household, and occupational) during the year preceding study recruitment. A total activity index (inactive, moderately inactive, moderately active, and active) was estimated by combining all activity types. Percent and absolute breast density were determined on screening mammograms using a computer-aided method. Multivariate linear regression was used to examine the association between physical activity and breast density. RESULTS: Mean percent density was 35.3% [95% confidence interval (95% CI), 31.8-38.8] for the inactive category compared with 36.1% (95% CI, 33.0-39.2) for the active category. Mean absolute density values for the inactive and active category were 45.8 cm(2) (95% CI, 40.9-50.7) and 42.6 cm(2) (95% CI, 38.3-47.0), respectively. Subgroup analysis for postmenopausal women showed similar results, as did separate analyses for recreational and household activity. CONCLUSIONS: The result does not support a relation between current physical activity and mammographic density in postmenopausal women.

Influence of estrogen receptor alpha and progesterone receptor polymorphisms on the effects of hormone therapy on mammographic density.

Postmenopausal hormone therapy increases mammographic density, a strong breast cancer risk factor, but effects vary across women. We investigated whether the effect of hormone therapy use is modified by polymorphisms in the estrogen receptor (ESR1) and progesterone receptor (PGR) genes in the Dutch Prospect-EPIC and the English EPIC-Norfolk cohorts. Information on hormone therapy use was obtained through questionnaires at recruitment and after 5 years. Blood samples were collected and consecutive mammograms were available through breast cancer screening programs. For 795 hormone therapy users, one mammogram before and a second mammogram during hormone therapy use was included. For 781 never hormone therapy users, mammograms with similar time intervals were included. Mammographic density was assessed using a computer-assisted method. Changes in density were analyzed using linear regression. A statistically significant difference in percentage density change between hormone therapy users and never users was seen in women with the ESR1 PvuII Pp or pp genotype (2.24%; P < 0.01), but not in those with the PP genotype (0.90%; P = 0.47). Similarly, effects of hormone therapy on percentage density were observed in women with the ESR1 XbaI Xx or xx genotype (2.20%; P < 0.01), but not in those with the XX genotype (-0.65%; P = 0.70). Also, effects were seen in women with the PGR +331 GG genotype (2.04%; P < 0.01), but not in those with the GA or AA genotype (0.98%; P = 0.53). The PGR PROGINS polymorphism did not seem to make women more susceptible to the effects of hormone therapy use. In conclusion, our results suggest that specific polymorphisms in the ESR1 and PGR genes may make women more susceptible to the effects of hormone therapy use on mammographic density.

Measurements of breast density: no ratio for a ratio.

Breast density, as visible on mammograms, is generally assessed as the occupied percentage of the breast and is a risk factor for breast cancer. Various studies have looked into the causation and alteration of relative density but the relation of a determinant with a relative measure does not allow a direct etiologic interpretation. It was our goal to compare the effects of known determinants on relative density and the absolute amounts of dense and nondense tissues. We measured the absolute and relative densities in a population of 418 postmenopausal women participating in a breast cancer screening program. The occupied surface area was calculated after manually tracing the contours of the tissues on digitized mammograms. Information on determinants was available through physical examination and questionnaires. Data were analyzed by multivariate linear regression. Age and parity were found to decrease the amount of dense tissue and the ages at menarche and menopause were found to increase it (R(2) = 13%). The amount of nondense tissue was increased by higher body mass index (BMI), age, and parity (R(2) = 43%). Relative density was affected by a combination of these factors (R(2) = 29%) with directionalities of effects that are comparable to those of dense tissue. However, the magnitudes of these effects were the resultant of the effects on dense and nondense tissues. The influence of BMI on relative density was completely due to an effect on nondense tissue. Although relative density is a relevant prognostic factor, inferences about the etiology of breast density should be made on the basis of absolute measures.

The 1944-1945 Dutch famine and subsequent overall cancer incidence.

Caloric restriction seems to be the most potent dietary intervention to protect against a variety of cancers in animals. We investigated whether overall cancer risk is affected in humans after exposure to a brief famine, followed by a period of abundance. We used data of approximately 15,000 women who were exposed at various degrees to the 1944-1945 Dutch famine at ages between 2 and 33 years. Between 1983 and 1986, these women were asked about their individual experiences of famine exposure ("absent," "moderate," or "severe exposure"). During follow-up until January 2000, 1,602 new cancer cases were identified by the regional cancer registry. We assessed the relation between famine and total cancer risk by weighted Cox regression models, in which a 15% random sample was used to represent person-years lived in the entire cohort. In these models, we adjusted for potential confounders. Overall cancer risk was increased in women having been severely famine exposed compared with women having been unexposed (hazard ratio, 1.25; 95% confidence interval, 1.01-1.55). Exclusion of breast cancer cases from our analyses showed that this increase in risk was largely driven by the previously reported increase in breast cancer risk: women who were severely exposed to the famine were at a 1.12 (95% confidence interval, 0.87-1.43) times increased risk of non-breast cancer compared with the unexposed. In conclusion, we found no indications that this brief famine has affected overall cancer risk, exclusive of breast cancer. Counteracting increased caloric intake following the famine, however, may have obscured any relation.